Proposal of the simplified area (SA) method for analyzing carnivore fecal composition

Abstract

The point-frame method is commonly employed to assess the dietary composition of carnivorous mammals in Japan. However, due to its time-consuming nature and dependence on microscopy for specific animal targets, there is a need for improvement. In this study, we introduce a novel technique, the ‘Simplified Area (SA) Method,’ and compare its efficacy with the point-frame method in analyzing fecal samples from the Japanese marten (Martes melampus). Fecal samples were preserved at –20°C in a freezer. Subsequently, extracted food items were dispersed onto a Petri dish, and the coverage of each food category was visually estimated and assigned scores as follows: 5 = over 50%, 2 = 10–50%, 1 = 1–10%, 0.1 < 1%. These SA scores exhibited a high degree of similarity (Whittaker’s percentage similarity (PS) > 75%) to the results obtained via the point-frame method. The key advantage of the SA method lies in its expedited processing time, requiring only approximately 5 minutes per sample, compared to the 20–30 minutes demanded by the point-frame method. Consequently, we advocate for the adoption of the SA method in carnivore fecal analysis, particularly for studies involving large sample sizes.